Illar Tenno, DVM Illar Muul, PhD
Much mystery surrounds the great increase in the numbers of ticks in the Baltic Region.
With this increase, diseases of people, transmitted by ticks, have also increased. These include viruses that cause fevers and encephalitis, and Lyme disease (named after Lyme, Connecticut, USA, where the cause of the disease was first described in 1982).Lyme disease is caused by spirochetes, which are smaller than bacteria, but larger than viruses.
In this article we will discuss Lyme disease and other similar infections .Lyme disease is being “discovered” in increasing numbers of localities throughout the world. This does not necessarily mean that the disease is spreading .Rather, the recognition and diagnosis of the disease is spreading.
Many medical reports are based only on clinical symptoms, often associated with the presence of a fever, swollen glands, fatigue, and a bite by a tick. Often a reddish rash surrounds the bite, but not always.
However, a growing number of cases of Lyme disease are being recognized that do not show all of the “text book” symptoms. In other cases, patients are not diagnosed and treated early enough and become very ill with long-term medical problems, affecting the eyes, nervous system, depression, and heart. Many of the long-term problems are thought to be the result of the immune system over reacting, called “auto-immune disease”. Even if the infection is ultimately recognized, treated, and eradicated, the medical problems sometimes persist.
The infection can become a life-changing event.
One such person we know spent a lot of time working in regenerating forests in Maryland, USA. In the early 1980’s he become ill, but Lyme disease was not widely recognized. He suspected an infection, but failure to diagnose it by a series of physicians led him to go to one of the best hospitals in the area. A series of screening tests led to a diagnosis: syphilis!! Impossible, he thought. He was treated with strong antibiotics and he was much better - - for a while.
Researchers now know that the organism that causes syphilis is fairly closely related to Borrelia burgdorferi , which causes Lyme disease. Both respond to the same antibiotics. And, both produce positive results in general screening tests. However, apparently because treatment was delayed for a long time, many of his chronic symptoms such as fatigue and depression have haunted him for decades and don’t respond to treatment.
Less recognized are infections in individuals who show no “text book” symptoms and many may, or may not, become chronically ill. One of the authors (IM) is such a case.
In late summer of 2009, he began having a localized pain behind his left ear while in Costa Rica. The pain persisted for days, and he had no other symptoms. He very seldom has headaches. He had removed an immature tick from his knee about a week earlier, but took no particular notice of it because it had not yet become engorged. Nor did any rash develop around the attachment site. He returned to the USA, with his headache, five days later. Because he seldom has headaches, he went to see his doctor. He was examined by MRI and electroencephalograph for possible circulatory problems, such as blockage that could lead to a stroke. Nothing was detected. He happened to describe his headache to a friend who told him that she had been previously diagnosed and treated for Lyme disease. She had typical, “text book” symptoms, but also a similar headache. IM requested his doctor to order a test (Western blot) for Lyme disease. The results were clearly positive. Anti-biotic treatment stopped the headache within 36 hours.
IM had studied a disease clinically similar to Lyme disease in Malaysia for six years (1968 – 1974): “scrub typhus“ (Orientia tsutsugamushi). Like Lyme disease this disease is also caused by spirochetes, but is not transmitted by ticks. The disease vectors are several species of chiggers (smaller relatives of ticks).
Both the Allied and Japanese forces suffered large numbers of casualties from scrub typhus during World War II throughout Southeast Asia. After the war the US Army Medical Research Unit (USAMR) was established to study this disease as part of the Malaysian Institute for Medical Research; soon a cure was found: Chloromycetin. Later clinical “scrub typhus” largely disappeared in the area. But, many questions remained.
IM and his colleagues wanted to study the disease in its natural environment. Though “clinical” scrub typhus disappeared when foreign forces left, mild forms of the disease had been recognized in scattered rural populations.
Studies of small mammals and chiggers that transmit the disease were found to be widely infected. Studies of forest-dwelling people (aborigines) found them to have high rates of antibodies. Since antibodies against scrub typhus do not last very long, the high antibody rates indicated frequent re-infections.
Attention was then turned to plantation workers who were in frequent contact with chiggers through their work. Studies were set up in health clinics and all patients were tested for antibodies and infections. Many patients who described flu-like symptoms were found to have scrub typhus. Almost none had “text book” symptoms and therefore were seldom diagnosed as having scrub typhus.
IM’s lack of any typical clinical symptoms for Lyme disease was apparently a similar situation. From childhood he spent much of his time in forests, studying nature. Later he became a professional ecologist. Very likely he encountered infected ticks on a regular basis and became infected starting in childhood. In the case of several diseases, such as, mumps, polio, scrub typhus, childhood infections are mild and often not diagnosed. But, if such diseases are acquired for the first time, as young adults or later, the consequences are often much more serious. For example, President Franklin D. Roosevelt and many others became crippled by polio. This occurred as a result of visits to areas with active infections where untreated sewage was discharged into ponds and lakes. People from urban areas with proper sanitation did not have immunity from childhood exposure.
We believe that Lyme disease has been present for a long time, but rural people who were exposed from childhood often did not become seriously ill. Unlike most viruses, Lyme disease does not produce permanent immunity. Vaccines provide only partial protection, reducing the severity of subsequent infections. This applies also to other spirochetes, bacteria and parasites such as Malaria.
We believe that Lyme disease became a clinically recognized problem when urban people began to move to the suburbs in large numbers. Those most severely affected were those who could afford a larger, wooded property, such as in Lyme, Connecticut. In upper New York State studies have shown that antibodies existed in 50 % of rural people who were not sick. In nearby towns, people seldom had antibody. In rural areas, very likely the vast majority of infections are not detected. Symptoms may be attributed to “arthritis”, or “old age problems.”
The problem of the increase in infections is compounded because former agricultural fields are becoming reforested. This provides more habitat for deer and small mammals and more opportunities for the vector ticks that they carry. Further, more people spend time outdoors in the attractive forested areas .Hunting is discouraged resulting in increasing deer and tick populations. Humans who become infected are not part of spirochetes life cycle, so they are called accidental hosts, or sometimes “dead-end” hosts (hopefully, not literally for us, but it is for the spirochetes.) This failure to complete the spirochete’s normal life-cycle seems to be a small bit of justice in the world.
Much more is known about the spirochetes that cause scrub typhus because of their war-time importance, and longer history of research. Both have very similar clinical symptoms .Both respond to the same medical treatment, usually high-dose tetracycline. And, both appear to have a large number of “silent infections” in a large portion of local, rural populations. Because rural people in Malaysia often became ill with flu-like symptoms when they actually had scrub typhus, local physicians became convinced that they were successfully treating flu with antibiotics. Of course, flu viruses are not affected by antibiotics, but the belief is deeply rooted.
We believe that more detailed epidemiological studies of Lyme disease would be useful, comparing urban and suburban people. Studies should differentiate frequency between age groups and the type of work done. Farm workers who are confined to dairy barns would be expected to have lower antibody rates than those who clear brush. Urban people who frequently go fishing, hunting, or bird watching would be expected to have higher risks. How long does antibody last? How frequent are re-infections in people at risk? How severe are infections in different age groups?
Even in USA, where Lyme disease has been recognized for a long time, many cases are not diagnosed early enough because patients often do not show all of the “text book” symptoms. We know of young girl whose family acquired a large, forested property in Maryland. At age 11 she began spending much of her time exploring and became ill. She had fever and the area around her ear became swollen, but no tick was observed. Her mother suspected Lyme disease because of her daughter’s outdoor activities. But, because no tick was found and the swelling was not surrounded by a rash, their physician did not prescribe an antibody test. The girl became more seriously ill, could not sleep properly, felt depressed, and eventually lost control of her arm. She had to drop out of school. Her mother sought other medical specialists, and finally found one who ordered the diagnostic test. It was positive and she was successfully treated.
We suspect that because the larval tick is small, it may have entered the ear canal and could not be seen. Of course, one should know what to look for.
Left untreated, Lyme disease can include autoimmune reactions which can become chronic and debilitating for many years, even if delayed treatment eradicates the parasites. Therefore, awareness of “silent infections” and more aggressive prescription of the antibody test are very important. Some patients say their whole life changed after having Lyme disease that was not diagnosed and treated early enough.
We would be happy to hear from readers their experience with Lyme disease. Next time we will discuss spirochetes, ticks, and how to control them.
Reference: Arno Karlen. Biography of a Germ. Anchor Books, 2000.
TICKS and LYME DISEASE --The Silent Epidemic (1)